Welding method and electrode



United States Patent I 3,231,709 WELDING METHOD AND ELECTRODE William R.Foley, Jr., Allison Park, Pa., assignor to The McKay Company,Pittsburgh, Pa., a corporation of Pennsylvania No Drawing. Continuationof abandoned application Ser. No. 211,428, July 20, 1962. Thisapplication June 17, 1963, Set. No. 288,075

6 Claims. (Cl. 219-76) This invention relates to a Welding method andelectrode. It relates more particularly to a Welding method andelectrode for forming a titanium carbide-containing hard fiacing welddeposit. This application is a continuation of my copendin-g applicationSerial No. 211,428, filed July 20, 1962, now abandoned.

The use of previously for-med hard metal carbides, particularly tungstencarbide, in hard facing Weld deposits has been practiced for many years.There are several methods by which such metal carbides may be bonded tosurfaces exposed to severe abrasion. In one type of hard-facingoperation a metallic tubular electrode packed with discrete carbideparticles is heated so that the molten metal carrying the carbideparticles can be deposited on the surface of the tool or part to behardfaced. This discrete, granulated particles of the previously formedhard metal carbide are thus trapped and imbed-ded in the metal suppliedby the container tube where they are bonded to the tool surface uponsolidification and result in an overlay of carbides cemented in place.This method of utilizing the excellent wear resistant properties of hardmetal carbides, usually tungsten carbide, has proven to be verysuccessful and is still widely used in special applications even thoughthe electrodes are expensive.

There are several disadvantages to this method of utilizing hardcarbides for wear resistant applications.

(1) The overlays of carbides cemented in place are of necessityrelatively high in concentration of metal carbide and the overlays,therefore, have mechanical properties similar to those of the metalcarbide, i.e., extreme brittleness, low shock resistance, poor oxidationresistance and low corrosion resistance in many media.

(2) With too high a temperature tungsten carbide particles tend tosettle to the bottom of the deposit due to their greater density,thereby leaving a soft top layer of bond metal. Gas welding is oftenpreferred to electric arc welding because the operation is slower andthe temperature can be more carefully controlled.

(3) A person highly skilled in the art of this type f deposition isrequired to obtain a satisfactory deposit as the temperature, time andwelding atmosphere (in the case of oxyactylene welding) are critical andmust be carefully controlled by the welder.

(4) The process is time consuming and is not economically feasible wherelarge surfaces are involved.

(5) T he electrodes are very expensive due to the high cost of preformedcarbides.

A second method of achieving high concentrations of hard metal carbidesin a deposit is one in which an applicator stick composed, for example,of metal oxide particles and carbon bonded t-ogether'is reacted andtransferred to the piece to be hard surfaced. The metal oxides areconverted to carbides by carbon present in the applicaice tor stick if asufficiently high temperature is maintained for the conversion to takeplace. This method of surfacing involves an external heat source whichproduces superficial melting of the surface of the piece to behard-faced While simultaneously heating the applicator stick andpreparing the carbide particles to be locked in place. The materialforming the applicator stick is thus spread over the surface of thepiece in .a layer of pasty consistency which, when solidified, traps themetal carbide particles.

This second method, in addition to having the same disadvantages whichcharacterize the bonded carbide deposits obtained by the first method,requires additional skill on the part of the welder to insure completetransformation of the metal oxide to the metal carbide and requires evenlonger times to satisfactorily surface a given area. This process isonly operable on surfaces that are at least nearly horizontal.

A third method of cementing hard metal carbides to surfaces is one inwhich a mixture of carbon and the metal oxide is merely sprinkled on thesurface of the piece. The mixture is heated while simultaneously meltinga superficial layer of the surface of the piece. Upon cooling thosecarbides that have been transformed from oxide are held in theresolidified surface of the piece.

This third method is even less attractive than the first two describedmethods because the quality of the deposit is dependent upon the skillof the welder to form the carbide particles and then superficially burythem in a melted surface film of metal and there is very little controlpossible.

In spite of the disadvantages stated above bonded carbide deposits havesubstantial utility, especially in highly abrasive applications wheretemperature, corrosive environment and impact are not factors.

Many successful alloy steel hard-facing Weld deposits have beendeveloped for applicationsinvolving heavy impact, severe corrosivemedia, elevated temperatures, or applications where large areas are tobe hard-faced. The high degree of abrasion resistance conferred bygrains of preformed hard metal carbides is absent but lack of suchcarbides must be countenanced in order to secure increase in impactstrength, corrosion resistance, high temperature strength, oxidationresistance and speed and ease of deposition. These properties areobtained by careful selection of alloying elements in the electrode. Asa group the alloy hard facing electrodes are successful and widely used.

Arc welding electrodes are typically coated wires or filled tubes. ItWas recognized long ago that these forms are substantially equivalent,the objective being to present to the weld locus the proper amounts ofweld metal, deoxidation elements such as aluminum, fluxes, whenemployed, and gas from some source for environmental control in casesuch control is employed.

It is common, as well known to those skilled in the art, to incorporatetitanium dioxide and/or metallic titanium in welding electrodes.Titanium dioxide has been used as a slag-forming ingredient and as anaid in the control of metal transfer. Metallic titanium, which isrecognized as having a high afiinity for oxygen and nitrogen, has beenused as a deoxidizer. The amount of titanium added for deoxidationpurposes is small and is determined by empirical methods as the amountsof oxygen and nitrogen present are not precisely determinable. .To

insure complete deoxidation, a slight excess of titanium may sometimesbe used. This may result in a residual concentration of titanium in theweld metal of up to 0.5- 0.6% Ti and, if the alloy happens to be highenough in carbon content, may cause the formation of some titaniumcarbide. The amount of such carbide when formed is very small and doesnot significantly affect the properties of the deposit.

I provide a method by which hard facing weld deposits can be fortifiedwith Wear resisting crystals of titanium carbide grown in situ in thecrystallizing weld metal. By this method substantially all theadvantages of the supporting hard facing deposit, such as impactstrength, corrosion resistance, elevated temperature strength, oxidationresistance and ease and speed of deposition, are retained while the wearresisting qualities of titanium carbide are added to deliver extraservice life.

V I provide a method of forming a wear-resistant weld deposit comprisingforming in an arc welding reaction zone a carbon-containing ferrous weldmetal pool, introducing into the reaction zone at least one of thematerials of the group consisting of titanium, titanium alloy and oxideof titanium, alone or combined with another oxide, and thereby formingtitanium carbide particles by crystallization in situ in the solidifyingweld metal which forms the matrix and maintaining in the reaction zonean amount of carbon at least equal to the total of (1) the amount ofcarbon required to form the titanium carbide particles plus (2) theamount of carbon required to satisfy the carbon demands of the matrixplus (3) the amount of carbon required to reduce titanium oxide andother metal oxides reducible by carbon if present plus (4) the amount ofcarbon required to combine with oxygen derived from the reaction Zoneatmosphere. The component which comprises at least one of the materialsof the group consisting of titanium, titanium alloy and oxide oftitanium, alone or combined with another oxide, contains titanium in anamount between about .8% and about 16% by weight of the weld deposit.Because the recovery efficiency factor for titanium is about 75% theelectrode contains titanium in an amount between about 1% and about 22%of the electrode metal weight. In terms of the weld deposit the totalamount of carbon is preferably equal to between about 1% and 9%. Becausecarbon may be required in the electrode for reduction purposes as wellas for deposit formation and because of the efficiency factor of about85-90% the total amount of carbon is preferably equal to between about1.1% and about 17% by weight of electrode metal. I also preferablymaintain in the reaction zone at least one of the following listedmetals in the stated percentage range.

Percentage by weight of Metal: weld deposit Nickel Trace to 22% maximum.Manganese 3% minimum to 18% Chromium Trace to 35% maximum. MolybdenumTrace to 8% maximum. Tungsten Trace to 4% maximum. Vanadium Trace to 2%maximum.

by crystallization in situ from the weld metal produced by theelectrode, the carbon being present in an amount at least equal to thetotal of (1) the amount of carbon required to form the titanium carbideparticles plus (2) the amount'of carbon required to satisfy the carbondemands of the m trix plus (3) the am unt of c rbon required to reducetitanium oxide and other metal oxides reducible by carbon if presentplus (4) the amount of carbon required to combine with oxygen derivedfrom the reaction zone atmosphere. As indicated above, such total amountof carbon is preferably equal to between about 1.1% and about 17% byweight of the electrode metal. The electrode preferably also contains atleast one of the metals above listed in the stated percentage range.

By incorporating in an electrode an appropriate source of titanium plusa requisite quantity of carbon, to be discussed later, it has been foundthat carbon and unexpectedly large quantities of titanium can bedissolved in the electrode metal and transferred across the welding arcand that significant quantities of titanium carbide particles can becrystallized in situ from the melt.

It has been found that the source of titanium can be either metallic incharacter or, advantageously from a cost standpoint, titanium oxide,alone or associated with other metal oxides, accompanied by free carbonto accomplish I its reduction. 7

By careful control of the carbon addition to an electrode, titanium, ineither the metallic or oxide form, can be readily converted to titaniumcarbide with no special technique or control required of the welder.Further, the deposition rates and electrode behavior are similar tothose of conventional hard-facing electrodes.

The wear resistance of any given alloy improves as the quantity oftitanium carbide increases. This has been demonstrated by a wear testingapparatus using standard abrasive paper. The increase in wear resistanceis small for concentrations of carbide less than about 1%. This lowerlimit of 1% is the effective threshold value at which significantincreases in wear resistance begin. Above 1% of titanium carbide theimprovement is marked and the ability of the welding operation toproduce titanium carbide in the deposit sets a maximum practical limitof about 20% titanium carbide. The lower and upper limits of titaniumcarbide, namely 1% and 20%, contain stoichiometrically .8% and 16%titanium respectively which are the limits of titanium previouslyspecified. The maximum value, coincidentally, falls in the lower rangewhere the deposit begins to assume the mechanical properties of thecarbide rather than of the matrix and to lose some of its metalliccharacteristics such as ductility.

For the purpose of calculating the amount of titanium to be added aselectrode metal it has been found in the practice of the invention thatthe recovery of titanium as titanium carbide in the weld deposit is ofthe order of three-fourths of the titanium added as electrode metal.

The following table shows examples of the wear characteristics ofseveral analyses with and without the presence of titanium carbideformed in situ from carbon and ferro-titanium and/or titanium dioxide.The tests were performed under standardized conditions. The weight lossis a measure of Wear resistance; the less the weight loss the better thewear resistance.

TABLE I Percent Average Titanium Weight Example Nominal CompositionAdded As Loss Electrode I (mg) Metal 1A 6% Cr, 4% M0, 3.5% 0 None 209. 4113-... 6% Cr, 4 0 M0, 3.5% C 1.1 123.0 1C- 6% Cr, 4% M0, 3.5% C 3. 593. 7 1D 6% Cr, 4% M0, 3.5% G 5.2 v 32. 3 2A 30% Cr, 3.5% M0, 3.0% None247. 5 2B 30% CI, 3.5% M0, 3.0% 5. 2 159. 5 3A. 13%01, 1.5% M0, 3 0%None 219. 2 3B 13%'Cr, 0.5% M0, 3.0% r 3. 140. 2 4A. 18% Or, 8 Ni, CNone 311.5 413 18% Cr, 8 Ni, 50% C 1.0' 219. 0

Computations of carbon required in the welding electrode system mustaccount for carbon used for these objectives:

(1) Forming titanium carbide,

(2) Supplying carbon for the matrix,

(3) Reducing titanium oxide and other metal oxides reducible by carbon(if present),

(4) Sacrificial protection against the atmosphere (if oxidizing).

Carbon used in excess of the amount required to fulfill theseobjectives, whether introduced deliberately or otherwise, is essentiallywasted and is not considered in the calculation of required carbon.

The very common and useful coated electrode can be employed in thepractice of the present invention. In this case small oxidation lossesdue to air are expected and provided for.

Certain welding systems, such as those employing gas shieldedelectrodes, reduce oxidation reactions to a very low level by floodingthe arc area with non-oxidizing gas, and my invention may be soemployed. In such case, since oxidation losses are low, most of thecarbon usually employed to react with the oxidizing atmosphere becomesexcess and may be omitted if desired. In other gas shielded weldingsystems in which the flooding gas is oxidizing, such as CO oxidationlosses approximate those of air.

Based upon deposit metal weight the minimum amount of carbon required inthe electrode to form 1% titanium carbide in a non-alloy steel matrix iscomputed as illustrated below, the source of titanium in this case beingmetallic titanium. Electrode metal is defined as the sum of the carbonand the metallic components either present in the electrode orrecoverable from compounds present in it. For simplicity in calculationsthe electrode metal weight is taken as equal to the deposit metalweight. This calculation is based upon a non-alloy steel matrix with theminimum carbon content necessary for the formation of 1% titaniumcarbide. If higher carbon contents are required by the matrix, and somecommon highly alloyed hard facing matrices require a carbon content ashigh as 5%, then the minimum carbon necessary for the formation of 1%titanium carbide must be increased by the amount of carbon required bythe matrix.

A. Carbon for formation of 1% TiC in deposit (item 1 above) 0.2% ofelectrode metal wt. B. Carbon requirement for non-alloy steel matrix(item 2 above) 0.8% of electrode metal wt.

C. Total A plus B 1.0% of electrode metal wt. D. Carbon efiiciency dueto sacrificial protection by carbon is typically 90% in low carbonranges (item 4 above). Therefore, minimum total carbon is 1.00-:-0.901.1% of electrode metal wt.

If titanium is introduced as titanium dioxide then additional freecarbon must be added to react with the oxygen. In the case of 1%titanium carbide in the deposit 1.8% titanium dioxide is necessary inthe electrode due to the recovery efliciency of titanium, which as aboveindicated is of the order of three-fourths of the titanium introduced.This amount of titanium dioxide would stoichiometrically require anadditional 0.3% carbon.

In similar fashion the upper limit of total carbon may be calculated. Asa practical matter it is governed by the amount of titanium oxide thatcan be incorporated in an electrode and be transformed to titaniumcarbide in a weld deposit while still retaining the desirable weldingcharacteristics required in a hard facing electrode.

This calculation for maximum carbon to form 20% titanium carbideparticles in a non-alloy steel matrix is illustrated below. Just as inthe previous calculation, if higher carbon contents are required by thematrix then the carbon necessary for the formation of 20% titaniumcarbide must be increased by the amount of carbon required by thematrix. The stoichiometric amount of titanium present in 20% titaniumcarbide is 16%. In order to make 16% titanium available to the deposit21.3% titanium from all sources must be present in the electrode as therecovery efficiency of titanium is of the order of Therefore, 35.5%titanium dioxide is stoichiometrically required.

A. Carbon required for reduction of 35.5% 'IiO in coating (item 3 above)5.3% of electrode metal Weight.

B. Carbon for formation of 20% TiC in deposit (item 1 above) 4.0% ofelectrode metal weight.

C. Carbon requirement for nonalloy steel matrix (item 2 above)disregarding presence of TiC .8% of electrode metal weight.

10.1% of electrode metal weight.

D. Total A plus B plus C E. Carbon efiiciency due to sacrificialprotection by carbon is typically in high carbon ranges (item 4 above).Therefore, maximum total carbon for a non-alloy steel background isl0.1+.85 11.9% of electrode metal weight.

In the case of a high carbon alloy steel matrix which would itselfrequire 5% carbon, the maximum total carbon required to produce adeposit containing 20% titan i-um carbide would be:

A. Carbon required for reduction of 35.5% TiO in coating (item 3 above)5.3% of electrode metal weight. B. Carbon for formation of 20% TiC indeposit (item 1 above) 4.0% of electrode metal weight. C. Carbonrequirement for high alloy steel matrix (item 2 above) disregardingpresence of TiC 5.0% of electrode metal weight. D. Total A plus B plus C14.3% of elect-rode metal weight.

E. Carbon efiiciency due to sacrificial protection by carbon istypically 85% in high carbon ranges (item 4 above). Therefore, maximumtotal carbon for a high carbon alloy steel background is 14.3+.85 16.8%of electrode metal weight.

serviceable,compositions to operate satisfactorily in any environment.Chromium in an alloy in an amount-up to 35% is suflicient to developcorrosion andoxidation- 22%; in the lower concentrations it servestoincrease the hardenability of the alloy while in the higherconcentrations it imparts toughness and stabilizes the austenitic phase.Manganese in an amount between 0.3% and 18% is normally used withnickel, chromium and molybdenum to produce toughness and, in the higherconcentrations, to produce austenitic structures which develop hardnessunder impact and good' wear resistance while retaining toughness.Tungsten over 4% and vanadium over 2% when present along with titaniumcarbide progressively alter the form and properties of the titaniumcarbide; under the limits stated both enhance harden- :abili-ty whiletungstenincreases hot hardness and vanadium helps control grain size.

The production of titanium carbide is technically possible in welddeposits containing the above stated elements atpercentages. higher thanthose given. However, the contribution to hard facing qualities whichthese elements can-confer are well developed within the limits statedand the use of higher concentrations would nor-- mally be construed aswasteful. The essential mechanism is operable in the presence of otherelements such as boron, columbium, copper and cobalt which arefrequently present in hardfacing matrices.

Certain residual elements normal to ferrous hard-facing deposits mayalso be present. The range-of silicon is commonly from 1% to 3% and inspecial cases may go higher. Small percentages of nitrogen are usuallypresent in hard facing weld deposits and any titanium nitride formedwould be associated with titan-iumcarbide as these compounds form acomplete. series of solid solutions. Phosphorus and sulfur maybe presentin typically commercial amounts.

In summary, an improvementin wear resistance is effected by thecontrolled formation of titanium carbide in any ferrous hard facingvcomposition.

Listed below are examples of three electrodes the wear resistingqualities of whose deposits were compared in Table I.

Example I.Depsit listed as Example 1D in Table I The electrode wasfabricated from a low-carbon steel core wire bearing a coating whosecomposition is listed below. The coating was 32.8% of the totalelectrode weight.

Parts by weight The deposit resulting had an increase in wear resistancefrom 209.4 mg. weight loss to 32.3-rng. weight loss produced intheformation of about 5%. titanium carbide in the deposit. In thiselectrode 4.7% of the electrode metal is present as carbon and 5.2% ofthe electrode metal is present as titanium.

Example lI.-Deposit listed as- Example 2B in TableI The electrode wasfabricated from a 12% Cr, 2% Mo, core wire bearing a coating whosecomposition is listed below. The coating, was. 31.4%.. of the total,electrode...

weight.

Parts .by weight Titanium dioxide 3T4 Ferrotitanium (42%. titanium)?Carbon 35 Ferrochromium (8% carbon) 218 Ferromanganese l8- Magnesiumcarbonate 2 Calcium carbonate 2' Silicate binder 39 The depositresulting had an, increase in wean resistance from.247.5 mg. weightloss.to.159.5'mg. weight loss produced by the. formation of about 5% titaniumcarbide, in the deposit. In this electrode 3.3 ofthe electrode metal ispresent as carbon and 5.2% of 'the electrode metal is present astitanium.

Example IIl.-Dep0sit listed as-Example3B in Table I The electrode wasfabricated r from 3.;1OWr carbon steel.

core wirebearing, a coating. whose composition is listed below. Thecoating; was 39% of the total electrode. weight.

Parts by weight The deposit resultinghad "an increase in-wear resistancefrom 219.2 mg. weight loss to 140.2'mg. weight loss produced by theformation of about 3.5% titaniumcarbide in thedeposit. In this electrode5.0% of the electrode metal is present as carbon and 3.7% of' theelectrode metalis present as titanium.

While I have described certain presentpreferredembodiments of myinvention and'certain present preferred methods of practicing thesame.it is to be distinctly'understood that the invention is-not limitedthereto but may be otherwise variously embodied and practicedwithin thescope, of the following claims.

I claim:

1. A method of forming a wear-resistant weld deposit comprising formingin an ,arc welding reaction zone a carbon-containing ferrous weld metalpool, introducing into the reaction zone a component comprising at leastone of the materials of the group consisting-oftitanium, titanium alloyandoxide of titanium, alone or combined with another oxide, suchcomponent'containing titanium in an amount between about .8% and about16% by weight of the weld deposit; and, thereby formingtitanium carbideparticles by crystallizationin situ; in' the solidifying weld metalwhich forms the matrix and maintaining inthe reaction zone an amount ofcarbon at least equal to the total of. (1) the amount. of carbonrequired to form the titanium carbide particles vplus (2) the amount ofcarbon required to satisfy the carbon demands of the matrix plus (3) theamount of carbon requiredto reduce titanium oxide and other metal oxidesreducible by carbon if present plus (4) the amount of 'carbon requiredtto combine with oxygen derived from the reaction zone. atmosphere.

2. A method of forming awear-resistant weld deposit comprising formingin an arc welding reaction zone a carbon-containing ferrous weld metalpool, introducing into the reaction zone a component comprising at leastone of the. materials of the group consisting of titanium, titaniumalloy and oxide of titanium, alone or combined with another oxide, suchcomponent containing titanium in an amount between about 1% and'about22%, by weight 'of'the electrode metal, and'thereby formingtitaniumcarbide particles by crystallization in situ in the solidifying weldmetal which forms the matrix and maintaining in the reaction zone anamount of carbon at least equal to the total of (1) the amount of carbonrequired to form the titanium carbide particles plus (2) the amount ofcarbon required to satisfy the carbon demands of the matrix plus (3) theamount of carbon required to reduce titanium oxide and other metaloxides reducible by carbon if present plus (4) the amount of carbonrequired to combine with oxygen derived from the reaction zoneatmosphere.

3. A method of forming a wear-resistant weld deposit comprising formingin an arc'welding reaction zone a carbon-containing ferrous weld metalpool, introducing into the reaction zone a component comprising at leastone of the materials of the group consisting of titanium, titanium alloyand oxide of titanium, alone or combined with another oxide, suchcomponent containing titanium in an amount between about 1% and about22% by weight of the electrode metal, and thereby forming titaniumcarbide particles by crystallization in situ in the solidifying weldmetal which forms the matrix and maintaining in the reaction zone anamount of carbon at least equal to the total of (1) the amount of carbonrequired to form the titanium carbide particles plus (2) the amount ofcarbon required to satisfy the carbon demands of the matrix plus (3) theamount of carbon required to reduce titanium oxide and other metaloxides reducible by carbon if present plus (4) the amount of carbonrequired to combine with oxygen derived from the reaction zoneatmosphere, such total amount of carbon being equal to between about1.1% and about 17% by weight of the electrode metal.

4. A method of forming a wear-resistant weld deposit comprising formingin an arc welding reaction zone a carbon-containing ferrous weld metalpool, introducing into the reaction zone a component comprising at leastone of the materials of the group consisting of titanium, titanium alloyand oxide of titanium, alone or combined with another oxide, suchcomponent containing titanium in an amount between about .8% and about16% by weight of the weld deposit, and thereby forming titanium carbideparticles by crystallization in situ in the solidifying weld metal whichforms the matrix, maintaining in the reaction zone an amount of carbonat least equal to the total of (1) the amount of carbon required to formthe titanium carbide particles plus (2) the amount of carbon required tosatisfy the carbon demands of the matrix plus (3) the amount of carbonrequired to reduce titanium oxide and other metal oxides reducible bycarbon if present plus (4) the amount of carbon required to combine withoxygen derived from the reaction zone atmosphere, such total amount ofcarbon being equal to between about 1% and about 9% by weight of theweld deposit, and also maintaining in the reaction zone at least one ofthe following listed metals in the stated percentage range:

Metal- Percentage by Weight 5. A carbon-containing ferrous metalelectrode for forming a wear-resistant weld deposit, the electrodecontaining as a component at least one of the materials of the groupconsisting of titanium, titanium alloy and oxide of titanium, alone orcombined with another oxide, such component containing titanium in anamount between about 1% and about 22% by weight of the electrode metal,and carbon to form titanium carbide particles by crystallization in situfrom the weld metal produced by the electrode, the carbon being presentin an amount at least equal to the total of (1) the amount of carbonrequired to form the titanium carbide particles plus 2) the amount ofcarbon required to satisfy the carbon demands of the matrix plus (3) theamount of carbon required to reduce titanium oxide and other metaloxides reducible by carbon if present plus (4) the amount of carbonrequired to combine with oxygen derived from the reaction zoneatmosphere.

6. A carbon-containing ferrous metal electrode for forming awear-resistant weld deposit, the electrode containing as a component atleast one of the materials of the group consisting of titanium, titaniumalloy and oxide of titanium, alone or combined with another oxide, suchcomponent containing titanium in an amount between about 1% and about22% by weight of the electrode metal, and carbon to form titaniumcarbide particles by crystallization in situ from the weld metalproduced by the electrode, the carbon being present in an amount atleast equal to the total of (1) the amount of carbon required to formthe titanium carbide particles plus (2) the amount of carbon required tosatisfy the carbon demands of the matrix plus (3) the amount of carbonrequired to reduce titanium oxide and other metal oxides reducible bycarbon if present plus (4) the amount of carbon required to combine withoxygen derived from the reaction zone atmosphere, such total amount ofcarbon being equal to between about 1.1% and about 17% by weight of theelectrode metal.

RICHARD M. WOOD, Primary Examiner.

1. A METHOD OF FORMING A WEAR-RESISTANT WELD DEPOSIT COMPRISING FORMINGIN AN ARC WELDING REACTION ZONE A CARBON-CONTAINING FERROUS WELD METALPOOL, INTRODUCING INTO THE REACTION ZONE A COMPONENT COMPRISING AT LEASTONE OF THE MATERIALS OF THE GROUP CONSISTING OF TITANIUM, TITANIUM ALLOYAND OXIDE OF TITANIUM, ALONE OR COMBINED WITH ANOTHER OXIDE, SUCHCOMPONENT CONTAINING TITANIUM IN AN AMOUNT BETWEEN ABOUT .8% AND ABOUT16% BY WEIGHT OF THE WELD DEPOSIT, AND THEREBY FORMING TITANIUM CARBIDEPARTICLES BY CRYSTALLIZATION IN SITU IN THE SOLIDIFYING WELD METAL WHICHFORMS THE MATRIX AND MAINTAINING IN THE REACTION ZONE AN AMOUNT OFCARBON AT LEAST EQUAL TO THE TOTAL OF (1) THE AMOUNT OF CARBON REQUIREDTO FORM THE TITANIUM CARBIDE PARTICLES PLUS (2) THE AMOUNT OF CARBONREQUIRED TO SATISFY THE CARBON DEMANDS OF THE MATRIX PLUS (3) THE AMOUNTOF CARBON REQUIRED TO REDUCE TITANIUM OXIDE AND OTHER METAL OXIDESREDUCIBLE BY CARBON IF PRESENT PLUS (4) THE AMOUNT OF CARBON REQUIRED TOCOMBINE WITH OXYGEN DERIVED FROM THE REACTION ZONE ATMOSPHERE.